Induction of apoptosis by U0126 treatment in HepG2 cells. HepG2 cells were grown and treated with either 0.1% DMSO (A) or 2 (B), 4 (C) and 6 (D) μM of U0126 in PSF medium for 48 h. Apoptotic cells were determined by TUNEL assay as described under Experimental Procedures. Apoptotic cells in 0.1% DMSO and U0126-treated samples were visualized under a fluorescent microscope. Representative samples are shown. Original magnification, ×200.